1. Field of the Invention
Aspects described herein relate to a link adaptation system and method which can adaptively cope with a changing wireless environment when the wireless environment including a location of a mobile terminal and the like is changed.
2. Description of the Related Art
A state of a wireless channel continuously changes depending on a location of a mobile terminal, a time, and a feature of fading. Accordingly, coping with the state of the changing wireless channel is needed for transceiving a large amount of data via a wireless link. Various methods are suggested in order to transceive data at high-speed, even when the state of the wireless channel changes.
In particular, research on a link adaptation method including an Auto-Rate FallBack (ARF) method is actively underway. The ARF method denotes a method of selecting a Modulation Coding Scheme (MCS) level in which a data rate is decreased when a source node fails to receive an Acknowledgement (ACK) message from a destination node at least a predetermined number of times.
The ARF method has a problem in that the MCS level cannot be quickly selected since whether the ACK message fails to be received the least a predetermined number of times is needed to be determined. Accordingly, the ARF method has a drawback of not easily coping with a change of the wireless channel due to a movement of the mobile terminal.
Also, a Signal to Noise Ratio (SNR) can be considered when the appropriate MCS level coping with the changing wireless channel is selected. Also, when the MCS level is selected based on the easily measured SNR, the SNR cannot be corrected when there is an error in the measured SNR. Accordingly, there is a problem in that the inappropriate MCS level is selected and the MCS level different from an actual channel is selected.
Also, since a method of selecting the MCS level based on the SNR needs to frequently measure the SNR due to the changing wireless channel corresponding to each data packet to be transmitted, hardware complexity is high and a load on a communication system is great.
Accordingly, a link adaptation system and method which can reduce the hardware complexity due to a need for frequently measuring the SNR, reduce the load on the communication system, and efficiently adapt to a changing wireless environment is needed.